1. Field of the Invention
The present invention relates to an image processing apparatus and, more specifically, to an image processing apparatus, a terminal, a printer apparatus and an image processing method that read an image of a document obtained from an original image, analyze conditions when the document was formed from a mark on the read image, and restore the state of original image from the read image based on the conditions.
2. Description of the Background Art
Recently, in corporate offices and the like, electrophotographic type MFPs (Multifunction Peripherals) attaining functions of facsimile, copying machine and printer have come to be installed and used.
Latest MFPs have a so-called N-up function, which will be described in the following.
The N-up function refers to a function of printing, when MFP prints image data on a sheet of paper, image data of a plurality of pages collectively on one sheet of paper. In the following, printing of image data of N pages (N is an integer larger than 0) on a sheet of recording paper will be referred to as “N-up printing.” By way of example, printing of image data of 2 pages and printing of image data of 4 pages collectively on a sheet of paper are referred to as “2-up printing” and “4-up printing,” respectively. Printing of image data of 1 page on a sheet of paper is a printing process not utilizing the N-up function. Even in such a case, such printing process may be referred to as “1-up printing” in the following.
The N-up function provided in an MFP can reduce the number of sheets to be printed. Therefore, cost and resources related to the recording paper can be saved.
It becomes desirable, as MFPs come to have the N-up function, to have an N-up printed document image turned back to electronic data, to process the electronic data as desired by the user and to have the processed data printed on a different sheet of paper.
In order to meet such a demand, Japanese Patent Laying-Open No. 2006-253973 (hereinafter referred to as “'973 application”) discloses a technique of determining whether a document read by a document reader of a copying machine has been N-up printed. According to '973 application, when image data of a plurality of pages are N-up printed, the image data are printed sectioned from each other by partition lines such as dotted lines. The copying machine described in '973 application determines whether the document has been N-up printed or not, depending on whether the partition line is drawn on the document. When the copying machine reads a document image and a partition line is found in the image, it divides the read document image data along the partition line. In accordance with a user instruction, the copying machine processes the divided image data and prints the data on different sheets of recording paper.
Japanese Patent Laying-Open No. 2004-304546 (hereinafter referred to as “'546 application”) also discloses a technique of determining whether a document read by a document reader of a copying machine has been N-up printed. According to '546 application, when a plurality of image data are N-up printed, a border line is drawn between each of the image data. The border line may be a solid line, a dotted line or a band-like blank line. The copying machine described in '546 application determines, when it reads images on a document, whether or not the document has been N-up printed, by determining whether or not there is a border line drawn on the document. If it is determined that the document has been N-up printed, the copying machine divides the image data along the border line, and in accordance with a user instruction, the copying machine processes the divided image data and prints the data on different sheets of recording paper.
To save resources, various documents in corporate offices come to be increasingly managed in the form of electronic data. By making documents electronically available, paper resources can be saved. Therefore, it is desired to have an image once printed on a sheet of recording paper turned back to the form of electronic data, to be stored and managed by a computer.
In that case, when the read image is turned to electronic data and the image data is displayed on a display, it is desirable that the displayed image data is in a direction easily viewable for the user. By way of example, assume that sentences are written on a document and the document image is turned to electronic data and displayed on a display. If the displayed characters are upside-down or laid-out sideways, handling of the electronic data can be troublesome for the user, as he/she must manually change or rotate the direction of image data on the display.
When an N-up printed document image is to be divided to the original image data and to be turned to electronic data, it is possible to utilize the techniques of determining whether or not N-up printing has been done, as described in '973 and '546 applications. Use of the techniques described in '973 and '546 applications alone is not sufficient, however, since the following problem arises. According to '973 and '546 applications, whether N-up printing has been done or not is determined simply by checking whether there is a partition line or border line. When the N-up printed document image is divided using such a determination method only, it is unknown whether or not the divided image data are fully restored to the state of original images before N-up printing. Therefore, simply by the technique described in '973 and '546 applications, the problem related to the restoration of images that have been turned to electronic data cannot be solved.